To obtain a one-pack type epoxy resin compsn. excellent in shelf stability at the low-to-medium temp. range and capable of forming a cured product excellent in properties through short-time curing by using a specific compd. as a curing agent.

This one-pack type epoxy resin compsn. contains as a curing agent a salt prepd. from 1mol imidazoline compd. and 1mol aliph. dicarboxylic acid. The salt prepd. from the imidazoline compd. and the aliph dicarboxylic acid, when used alone as the curing agent, is used in an equivalent amt. of 0.15 to 0.80mol per epoxy groups in the epoxy resin compsn. 2-Phenylimidazoline is esp. suitable as the imidazoline compd. Adipic acid is esp. suitable as the aliph. dicarboxylic acid.